[aprssig] Draft Copy of Thesis on APRS

[Curt Mills]

I didn't see mention of the datum problem, where changing the earth
datum on a handheld GPS changes the numbers for the posit on the
serial port due to the datum shift.  If we all used WGS84, it wouldn't
be a problem.  Unfortunately sometimes other datums fit our maps
better, which changes the coordinates out of the GPS serial port and
into the APRS TNC's.

Section 7.2.4 says that proportional pathing is the norm for APRS
trackers.  It _might_ be the norm for APRS digipeaters, but not for
trackers.  Most trackers use fixed-period, or else SmartBeaconing(tm).

-- 
Curt, WE7U